2.3 Notes & Guidance
Amiodarone has a very long half-life (extending to several weeks). Following an oral loading dose (e.g. TDS for 1 week then BD for a further week) maintenance doses are administered ONCE DAILY.
Dronedarone has recently been licensed to treat adults with a history of or current non-permanent AF either to prevent recurrence of AF or lower ventricular rate.
It has been compared with amiodarone in a clinical trial and found to be less effective than amiodarone but with fewer adverse effects.
Dronedarone is considerably more expensive than standard treatments hence it should only be used in accordance with NICE guidance (see below).
Dronedarone is recommended as an option for the maintenance of sinus rhythm after successful cardioversion in people with paroxysmal or persistent atrial fibrillation:
- whose atrial fibrillation is not controlled by first-line therapy (usually including beta-blockers), that is, as a second-line treatment option and after alternative options have been considered and
- who have at least 1 of the following cardiovascular risk factors:
- hypertension requiring drugs of at least 2 different classes
- diabetes mellitus
- previous transient ischaemic attack, stroke or systemic embolism
- left atrial diameter of 50 mm or greater or
- age 70 years or older and
- who do not have left ventricular systolic dysfunction and
- who do not have a history of, or current, heart failure.
The MHRA Safety Update October 2011 advises that the benefits of using dronedarone now only outweigh the risks in a limited population of patients with paroxysmal or persistent atrial fibrillation.
Dronedarone is now contraindicated in patients with:
- Unstable haemodynamic conditions
- History of, or current, heart failure or left ventricular systolic dysfunction
- Permanent AF (ie, duration ≥6 months or unknown, and attempts to restore sinus rhythm no longer considered by physician)
- Liver and lung toxicity related to previous use of amiodarone
The MHRA now recommends regular cardiac, hepatic, renal and pulmonary monitoring (see below)
- Patients should receive regular cardiac examinations, including an ECG at least every 6 months, to identify those who revert to AF. Discontinuation of dronedarone should be considered for these patients
- Patients should be carefully evaluated for symptoms of heart failure during treatment
- Liver-function tests should be done: before starting treatment with dronedarone; after 1 week of treatment; after 1 month of treatment; then every month for 6 months; at month 9; at month 12; and periodically thereafter
- Plasma creatinine values should be measured before and 7 days after initiation of dronedarone, and renal function should be monitored periodically afterwards. Discontinue treatment in any patients with further elevations of serum creatinine
- Cases of interstitial lung disease, including pneumonitis and pulmonary fibrosis, have been reported in association with dronedarone. Onset of dyspnoea or non-productive cough may be related to pulmonary toxicity. If pulmonary toxicity is suspected during treatment, relevant lung examinations should be considered and treatment discontinued if confirmed.